KUALA LUMPUR - Malaysia's AirAsia X Bhd plans to drop a local airport operator from its $15.3 billion debt restructuring plan to expedite discussions with creditors as its cash is running out fast, people with direct knowledge of the matter said.

The budget carrier is seeking to reconstitute the $15.3 billion of unsecured debt into a principal amount of 200 million ringgit ($48 million) and have the rest waived.

But Malaysia Airports Holdings Bhd (MAHB) filed a lawsuit last week to claim 78 million ringgit ($18.74 million) owed by AirAsia X and a separate application to be excluded from the restructuring scheme, arguing that its debts were secured.

A source, who was not authorised to speak publicly about the plans, told Reuters the legal action against the airline could delay its plan to restructure debt to stave off liquidation.

The source said AirAsia X, the long-haul arm of AirAsia Group Bhd, has less than six months of cash left and has been looking to convene a meeting of creditors to vote on the scheme.

"It needs to move on and have that meeting as soon as possible," the person said.

"Fundraising is expected to take a couple of months at least so it's imperative for the company to complete restructuring by January or February."

AirAsia X declined to comment.

Airport operator MAHB said on Sunday its attempt to recover debt from AirAsia X would not derail the airline's scheme. But the legal suit follows similar action taken by another creditor.

Aircraft lessor BOC Aviation Ltd filed a lawsuit against AirAsia X and its subsidiary in August to claim $23 million in debt and this month applied to intervene in the airline's court application for its scheme.

The airline's restructuring proposal needs approval from creditors holding at least 75% of the total value of the debts, and the source said that the bulk of the figure is linked to future aircraft orders and it gives Airbus SE nearly 75% on its own.

"No creditor will want to make a decision if they don't know what the outcome with MAHB is," another source said, adding that MAHB could have the financial stamina for a legal battle but AirAsia X did not.

The sources said that the airline was hoping there would be no other new legal action that might impede the proposed creditors' meeting.

Post restructuring, the airline plans to raise up to 500 million ringgit to restart the company, it said on Monday. ($1 = 4.1630 ringgit)

(Reporting by Liz Lee Editing by Miyoung Kim and Jamie Freed) ((liz.lee@thomsonreuters.com; Desk: +60323338039; Twitter: @livinglizly;))